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April 28, 1925.

E. OHARA APPARATUS FOR ENAMELING ARTICLES 2 Sheets-Sheet 1 Filed Feb. 18. 1924 M, 0 d i -c.

'April 28, 1925. 1,535,850 E. OHARA APPARATUS FOR ENAMELING ARTICLES Filed Feb. 18. 1924 2 Sheets-Sheet 2 INVEN'LEH/ Patented Apr. 28, 1925. l

ELIOT OHARA, OF WALTHAM, MASSACHUSETTS.

APPARATUS FOR ENAMELING ARTICLES.

Application filed February 18, 19%. Serial N'o. 693,588

To all whom it may comem Be it known'that I, ELIOT OHARA, a citizen of the United States, residing at Waltham, county of Middlesex, State of Massachusetts, have invented a certain new and useful Improvement in Apparatus for Enameling Articles, of which the following is a specification, reference being had therein to the accompanying drawings.

The invention relates especially to coating articles with vitreous enamel and firing the same in a furnace but the invention is adapted for use in coating and baking numerous other kinds of articles made of wood or other base material which are to be coated with a paint, varnish, baking enamel, lacquer, or other material and which latter is to be dried, fired, burned or hardened by heat or some other agent.

Formerly such goods were first coated and then, by hand, removed from the trays or holding jigs upon which they are sprayed, painted or dipped or otherwise coated and placed upon other trays, planches, plaques or conveyors on which they are held while being baked. The holders on which the articles were held while being coated also became coated as well as the articles so that if the articles were subjected to the heat while still supported on the same holders, the coated material would harden to the holders. as well as to the work. For this reason it was necessary to provide a clean conveyor or holder for the articles While undergoing the heat treating process and one which would sometimes have to withstand high temperatures.

lft is preferableto have a continuous operation from the application of the coating material to the passing of the articles through the furnace and conveying them away from the furnace in order to avoid the handling of the articles by hand.

When one continuous conveyor is used on which the article stands while the coating is being applied and which carries the article through the furnace and discharges it and then returns to receive other articles to go through the same process, the conveyor as well as the article becomes coated and the coating is baked on the conveyor as well as soon becomes covered with a thick coatin' which renders the conveyor much less usefu for its intended purpose, clogging it up, making it less flexible as well as heavier and preventing it from running smoothly and also causing the enameled article to stick to the conveyor. The object of the present invention is to provide a separate conveyor for carrying the articles into and through the furnace from that which holds the articles during the application of the coating so that the conveyor which is subjected to the heat is always clean, while the conveyor which holds the articles during the application of the said coating material will not be subjected to the heat and, therefore, any coating material which. falls onto it while the articles themselves are being coated will not harden enough so but thatitmay be removed. Another object is to so construct and arrange the two conveyors with relation to each other that the freshly coated articles will be transferred automatically from one conveyor to the other without vibration or jar as that tends to disturb the smoothness of the coating before it is baked and consists in so interlapping the two conveyors that during the transition the article will for a time stand on bothconveyors atthe same time. Another feature of the present invention consists in means for cleaning the first con- TIE veyor on which the article receives its fresh coating while it is making its back run preliminary to receiving and carrying forward another article. Another feature consists of making the first conveyor of metallic wires that are especially adapted to resist adhesiveness of the coating material.

Another feature of the invention consists in forming the conveyor which carries the articles into the furnace of material which has a much higher heat resistance than the conveyor which is not exposed to the heat.

Another feature of the invention consists of means for treating the conveyor wires which pass through the furnace to prevent the enameling material from sticking to them. Other features will be more particularly set forth hereinafter.

The invention will for convenience be particularly illustrated and described in connection with apparatus for use in enameling articles, it being understood that the form of apparatus may be varied for application to coating articles with other material than enamel and then baking them.

The invention will be fully understood from the following description of one form or embodiment thereof illustrated in the accompanying drawings and the novel features thereof will be pointed out and clearly defined in the claims at the close of this specification.

In the drawings:

Fig. 1 is a diagrammatic side. View of apparatus embodying the invention.

Fig. 2 is a plan view of Fig. 1.

Fig. 3 is a section taken on line 3-3, Fig. 1, showing the conveyor passing through the furnace.

Fig. 4 is a side elevation of a modified form of apparatus showing both spraying and sifting means for applying the enamel.

Fig. 5 is a side elevation in diagram showing two successive sets of apparatus for coating and baking the articles for use where more than one coat is desired;

v Fig. 6 is a side elevation showing in diagram a modified form of conveyor.

Fig. 7 is a section taken on line 7-7, Fig.

Referring now to the drawings: In Figs. 1, 2 and 3 there are shown three rotary cylinders 1, 2 and 3, respectively, each mounted on a horizontal axis and each cylinder being formed with peripheral grooves 5, 6 and 7 respectively, to receive and guide the wires of the conveyors. The wires shown in the drawings are circular in cross section. They may, however, be flat or of any other cross sectional contour. The word wire is used herein in a broad sense whether the wire be in the usual form of a round wire or flat in the form of a ribbon. Also a cable or chain I regard as an equivalent of what may be strictly covered by the term wire. The first set of conveyor wires 8 are looped around the cylinders 1 and 2, the grooves in the respective cylinders keeping the wires properl%spaced apart and parallel with each other. referably the grooves are quite close together so that the. wires will be only a short distance apart from each other. It is to be noted that the wires 8 engage only -with alternate grooves in the cylinder 2,

the other alternate grooves in said cylinder 2 being left for the second set of conveyor wires 9. The second set 01' conveyor wires 9 are looped around cylinder 2 and around the cylinder 3. Itwill thus be seen that the loops of the wires 9 around the cylinder 2 alternate with the loops of the wires 8 around said cylinder so that there is a short length in the upper run of both sets of wires during which the two sets of wires run parallel with each other on the same level and in alternating arrangement so that an article in passing from the conveyor wires 8 to the conveyor wires 9 will for a short distance equal to the length of the overlapping portions of the twosets of wires ride on both sets of wires. The grooves on the cylinder should be of less depth than the diameter of the wires so that the wires will project above the grooves suificiently to contact with the bottom of the article. Preferably the axes of the three cylinders 1, 2 and 3 are parallel with each other and in the same horizontal plane so that the upper run of both sets of conveyor wires will be in the same horizontal plane. The wires 8 and 9 are each shown as one continuous Wire looped back and forth around the cylinders. It is obvious that there may be employed a plurality of separate parallel endless wires. For convenience of description the several runs of thewire 8 will be referred to as wires even though it is one continuous Wire. For the same reason the several runs of each of the conveyor wires will be referred to as wires."

In order to keep the wires taut there are preferably provided tension pulleys 10, 11 respectively for the two sets of wires.

At 12' is shown a kiln or furnace intermediate the cylinders 2 and 3 through Which the conveyor wires 9 pass in their upper run, the lower run of said wires being below the furnace.

The articles 13 which are to be enameled are placed on the lirst set of conveyor wires 8 where they receive the enamel. There is located above the first set of conveyor wires 8 suitable means for applying to the articles the enamel while the articles stand on the wires. The enamel may be either in the form of a powder which is sifted on or in the form of a liquid which is sprayed on. For application to (lat surfaces or to other surfaces which will hold the powder long enough to go through the cnameling process, it is usual to employ the powder and to sift it on. For application to vertical sides or to other parts which will not hold the powder, it is preferable to spray it on in liquid form. In Fig. 1 there is shown a spraying device 15. In Fig. 4 there are shown both a'spraying device 15 and a sifting device 25.

The wires 9 which go through the furnace should be made of some suitable metal which Will withstand a high temperature. Some of the suitable materials for these wires are alloys consisting of chromium and steel. nickel and steel, and chromium and nickel. These are merely specimens of suitable material and it is not intended herein to be limited to the use of any particular metal or any particular alloy. Any metal which will stand the high temperature required may be employed. There is no objection to the use of material of high heat resistance for the wires 8 except that it is not necessary to make use of wires of such expensive materiel as required for the wires 9. It is, however, desirable that the wires 8 should be of some non-corrosive material when spraying is employed, and of some material to which 'the powder will not stick when sifting is employed. When the. spraying method is used bronze or copper is a desirable metal to use in order to withstand the corrosion from the liquid. When the sifting method is employed polished steel is a ,good metal and whatever metal is employed with the sifting method it is better that is should be'polished because less powdered material will cling to the wires if polished than if unpo-lished.

As it is desirable to keep the wires 8 as clean as possible, I'provide means whereby the wires are cleaned off during each round of their travel. To this end there is provided a scraper, preferably in the form of a brush 16 located in the path of the under run of the wires on their return travel which will engage the wires to remove, so far as possible, any remaining enamel. For convenience the term brush will be used herein to-include any suitable device for removing the enamel.

There are preferably provided means for,

treating the wires which run through the heating chamber or furnace to. prevent the freshly coated-article from sticking to the wires. For this purpose there is provided a tank 17 located at some distance below the under run of the wires 9, preferably about midway of its under run, said tank containing a bath of some suitable substance which, when applied tothe wires will render them less liable to have the enamel stick to the wires. A good mixture for this purpose is chalk or whiting mixed with water. At 18 is shown the level of such a mixture in the tank. A guide cylinder 19 is pro vided which is partially submerged in the liquid solution in the tank, said guide being grooved to correspond with the grooves of the cylinder 3 and the wires are of suflicient length so that they will run under the said guide 19 and thereby be caused to dip into the mixture in the tank at each under run movement of the wires and receive a fresh coating of the anti-stick material.

Any suitable means may be employed for driving the conveyors. One form is shown in Fig. 1. A pulley 27 is mounted on the shaft 28 of the cylinder 3 and is driven by a belt 29 connectedwith any suitable source of power. The friction of the wires on the cylinder will drive the other cylinder and the wires.

Sometimes it is desirable to apply two entirely independent coatings of enamel and to bake the coating of the first before the second is applied. The arrangement of apparatus for thus applying a succession of coatings and baking them on is shown in Fig. 5. In this arrangement there are provided as heretofore described the cylinders 1, 2 and 3, wires 8 running around the cylin' ders '1 and 2 on which the article is held while the first coat of enameling material is applied and then it is conveyed through the furnace 12 by the conveyor wires 9. Instead of being then discharged from the con veyor wires 9, there is provided another cylinder 2* having a set of wires 8 which run over the cylinders 3 and 2*, and a cylinder 3 having a set of high resistance wires 9 which run over the cylinders '2 and 3 and a furnace 12 through which the articles are carried b the wires 9 after the articles have receive the coating of enameling material while on the wires 8. Thus the article will be carried from the first station automatically through both furnaces without interruption, receiving a coat of the enameling material previous to passing through the first furnacewhere it is baked and then receiving another coat of enamel before it passes through the second furnace where the second coat is baked. It will finally be discharged from the conveyor 9 at the end of the upper run.

It is sometimes desirable to run the two sets of conveyor wires at different speeds. Particularly it is sometimes desirable to have the articles moved at a faster speed while goin through the furnace than while receiving tie coating of" enamel on the-first set of wires; In order to accomplish this resultthe'interlapping portions of the two sets of wires run over independent cylinders which are driven at different speeds. Such an arrangement is shown in Fig. 6 in which the wires, 8 run over the two cylinders 21, 22 and the wires 9 run over the cylinders 23, 24, the cylinders 23 being intermediate the cylinders 21 and 22 so that the two sets of wires will lap each other for the purpose of making the transfer of the articles from one set of conveyor wires to the other.

The cylinders 22 and 24 can be driven by any suitable means independently of each other and at any relative speed desired. As shown in the drawings the cylinder 22 is formed with two sets of grooves 30, 31 for the two sets of wires, the grooves 30 being for the wires 8 and the grooves 31 for the wires 9. The grooves 31 are deeper than grooves 30 and give clearance for the wires 9 so that the wires 9 will not bend on the cylinder 22 as they pass from cy inder 23 to cylinder 24, yet they run side by side with the wires 8 for a short distance so as to permit the transfer of the articles as previously described. The cylinders 24 and 23 and conveyor wires 9 are driven b belt 29 through pulley .32 in shaft 33 whic 1 carries the cylinder 24. The cylinders 21 and 22 and wires 8 are driven by belt 29 through pulley 34 on shaft 33, pulley 35 on shaft 36 of cylinder 22 and belt '37. The pulley 34 is smaller than pulley 35 and thereby the speed of conveyor wires 8 is -whether such rotary members are technr cally cylinders or whether they be pulleys or wheels.

\Vhat I claim is:

1. Apparatus for enameling articles having a conveyor vfor supporting the articles while receiving the coating of enamel, a second conveyor onto which the coated articles are transferred automatically from the said first conveyor and a furnace through which the articles are carried by the second conveyor, each conveyor having a plurality of parallel runs, the adjacent ends of the runs of the two conveyors lapping past each other for some distance in such manner that the lapping portions of each run of each conveyor will be intermediate two runs of the other conveyor.

2. Apparatus for enameling articles having a conveyor for supporting the articles while receiving the coating of enamel, a second conveyor onto which the coated articles are transferred automatically from the said first conveyor, and a furnace through which the articles are carried by the second conveyor, each of said conveyors consisting of endless wires having a plurality of parallel runs,-the adjacent ends of the runs of the two sets of wires lapping by each other in alternating arrangement in such manner that one or more wires of each set will have a runway intermediate the runways of two of the wires of the other set, so thatthe coated article will ride at the same time on both conveyors where they overlap, and means for supporting the loops of the wires at the two ends of the run.

3. Apparatus for cnameling articles havmg a conveyor for supportin the articles while receiving the coating 0 enamel material, a second conveyor onto which the coated articles are transferred automatically from the said first conveyor, a furnace through which the articles are carried by the second conveyor, and which carries the articles through the furnace, each of said conveyors consisting of endless wires having a plurality of parallel runs, the adjacent ends of the runs of the two sets of wires lapping by each other so that the article will ride at the same time on both conveyors where they overlap, and means for supporting the loops of the wires' at the two ends of the run, the wires which pass through the furnace being composed of metal of a sufficiently high heat resistance not to be melted by the heat of the furnace.

4. Apparatus for enameling articles having a conveyor for supporting the articles while receiving the coating of enamel, a second conveyor onto which the coated articles are transferred autmmticaily from the said first conveyor, a furnace through which the articles are carried by the second eonveyor, each of said conveyors consisting of endless wires, means for applying powdered enameling material to the article while on one set of wires, the wires which form the conveyor on which the articles are supported while receiving powdered enameling material being of polished metal.

In testimony whereof I affix my signature.

ELIOT OHARA. 

